It started a dozen years ago when Shumway Marshall wanted to give his two sons an antique horse-drawn wagon for Christmas. "My dad and I went to look for a wagon," Sutton "Sut" Marshall '64 recalls. "We found nine wagons in a collection, and we couldn't decide. So we bought all nine." That was the beginning of a labor of love for Marshall and his wife, Margaret '67.

It's fair to say that wagons run in the family. When Shumway Marshall was a boy, he grew up on a dairy farm outside Colebrook, N.H., and used to take the milk into town with a wagon or, in the winter, a sleigh. Today, Sut and Margaret Marshall, who own Abbot Dairy in Conway, N.H., still drive a horse now and then, usually with a two-wheel Meadowbrook cart.

They keep their collection of 175 wagons in a climate-controlled exhibition hall in Conway and a barn at Maine's Fryeburg Fair where, in 2004, they exhibited some 20 of them, including a bread wagon, butcher's cart and a magnificent green and gold English gypsy wagon.

The 100-year-old gypsy wagon—literally a house on wheels—is everyone's favorite, according to Marshall. "It's very ornate inside and out, and even has a bunk for a small child," he says. "The gypsies would park along a road and camp there until asked to move." He adds that gypsy wagons are very hard to find today because, as part of the gypsy tradition, a wagon and other possessions were normally burned when their owner died.

For this year's Fryeburg Fair in early October, the Marshalls are exhibiting a different assortment, including an ice cream wagon and a rare children's amusement ride lorry. The Marshalls have "the premier collection in the country," says Ken Wheeling of Monkton, Vt., an authority on antique vehicles. He has special praise for their commercial vehicles. "There are 20 to 25 English commercial vehicles and a fire engine collection—an 1835 hand pumper piece, two steam pumpers and ladder wagons. The breadth is astonishing."

The Marshalls tracked down vintage wagons by attending auctions, following up on leads and working with an agent in England. "The days of finding a Concord Coach in someone's barn are pretty much over," says Marshall. They originally hoped to turn their collection into a museum: instead they now give occasional tours by appointment.

At this point, their collection is "way out of control," Marshall admits ruefully. He says they don't plan to buy any more wagons just now. Or, he adds with a mischievous grin, "At least until the phone rings."